How can I make face uv orientation clearer?
There are two much easier things you can do to visualize the direction that faces are pointing than change the user preferences.

The first is activating the normals.



Now every face will have a blue line pointing in the direction it is pointing.

The other thing you can do is enable Backface Culling.



Here I have added some loop cuts so that there are more faces to see.

If one is inverted, and pointing inward, you will also see through it. this is good for working in the BGE where faces pointing inward will make your mesh look really weird.